Aug 5, 2025
Is bigger always better when it comes to strength training? In this episode, Amy Hudson and Dr. James Fisher break down the science of muscle growth, revealing why increased size doesn’t always equal increased strength.
From neural adaptations to muscle fiber recruitment, they explore what’s really happening inside your body when you train – and why understanding it can transform the way you approach your workouts.
- Amy Hudson and Dr. James Fisher talk about increasing muscle size, and when that doesn’t happen.
- Back in the 1980s, a hypothesis by Digby Sale looked at the two key adaptations most people are interested in when it comes to growing their muscle.
- Hypertrophy is an increase in muscle size.
- Dr. Fisher explains that, “When we begin strength training, almost 99% of our adaptations and increases in strength are neural.”
- Dr. Fisher goes on to say that at some point our hypertrophic adaptations, or increase in muscle size, will kick in which can lead to an increase of muscle strength as well.
- Did you know that most people aren’t able to recruit 30% and maybe 90% of their muscle fibres.
- Dr. Fisher touches upon a project that looked at the different reactions (and results) between people used to exercise and some who typically don’t…
- “The increase in force and the increase in ability to produce force is a product of our ability to send continued, sustained and higher frequency impulses from our brain to our muscle fibers,” says Dr. Fisher.
- There are different structures within a muscle: the muscle fascicle, the muscle fiber, and the myofibrils. A 1-2% change in one of them doesn’t equal a change in the whole muscle.
- Dr. Fisher and Amy go through each muscle structure and its role within strength training and in the muscle growth process.
- It’s good to note that “myo” refers to muscle, so myofibril, for instance, refers to a fibril within a muscle.
- Hypertrophy revolves around an increase in size, while hyperplasia has to do with an increase in numbers.
- There’s some evidence around hyperplasia, though many people still question whether it truly exists.
- Did you know that somebody that has average size in muscles but is very strong has arguably better muscle quality than somebody who can produce the same amount of force but has much bigger muscles?
- The conversation touches upon two ways to measure muscle growth, “in vivo” and “in vitro,” as well as muscle architecture, the motivators for wanting to increase the size of one’s muscle, and the pennation angle of our muscles.
- For Dr. Fisher, strength training is wasted on people that just want bigger muscles, as it’s a superficial acceptance or adaptation to strength training.
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Previous episode - Beyond the Gym: The Role of Protein in Personal and Strength Training Success
Previous episode - Evidence-Based Strength Training: Ditching Old Paradigms for Proven Success
Identifying the Structural Adaptations That Drive the Mechanical Load-Induced Growth of Skeletal Muscle: A Scoping Review by Kent W. Jorgensen et al. 2020
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